The sinking of Concordia- 'It WAS a microburst,' says expert

by Canadian Press/Sail-World Cruising on 5 Apr 2010 A U.S. meteorologist who studies rare weather phenomena says he is now convinced a Canadian-based 'sailing school' was hit by an intense blast of air moments before it sank off the Brazilian coast.

The crew and students from around the world who were sailing on the tall ship Concordia on February 17th this year as part of their studies, described scrambling out of the crippled tall ship as it bobbed on its side in squalls after being hit by heavy winds.

They quickly climbed into several life-rafts before the vessel went down about 20 minutes after it capsized. All 64 people on board got off the vessel safely, but had to endure more than 40 hours at sea before being rescued by Brazilian officials.

Ken Pryor of the National Oceanic and Atmospheric Administration studied satellite and global forecast system data from Feb. 17, the day the Concordia went down 500 kilometres from shore with 64 crew and students on board.

Pryor found the data showed three key weather conditions came together to cause a severe microburst or downburst that likely hit the ship with downward winds in excess of 120 km-h.

'I'm very certain that this was a severe downburst to be able to capsize a ship like that,' he said from his office in Camp Springs, Maryland.

'I was able to identify satellite signatures or features that corresponded directly to microburst occurrence.'

Those features included a notch of dry air that was being channelled into a thunderstorm, providing the energy for potent winds that blew down on the 57-metre training ship.

The notch was 'pointing directly to the location of the Concordia and thus, the vessel was in the direct path of downburst winds,' Pryor said on his blog, which contains satellite imagery of the weather features.

Crew had suspected a microburst struck the ship because of the intense winds that blasted quickly down on them after midday as some rested in their bunks or attended classes on the floating school.

But they hadn't before had an analysis of satellite data to support their suspicions.

'It confirms for me the narrative that was initially reported back to our office by our captains and crew,' Nigel McCarthy, president and CEO of Class Afloat, the company that runs the program, said from Lunenburg, N.S.

'We 've always believed that it was an extreme weather event and suspect that the investigation may well bear that out.'

McCarthy said he didn't believe any of Class Afloat's vessels had experienced a microburst before.

Pryor, who has written about and teaches a course on the phenomenon, said microbursts of 70 km-h or less are not unusual, but downbursts that contain winds in excess of 120 km-h are rare.